1. Field of the Invention
The present invention relates to a light-emitting diode (LED) light source and a backlight module using the LED light source, the backlight module typically employed in a liquid crystal display.
2. Discussion of the Related Art
In a liquid crystal display device, liquid crystal is a substance that does not itself generate light. Instead, the liquid crystal relies on light received from a light source in order to provide light to display images and data. In the case of a typical liquid crystal display device, a backlight module powered electrically supplies the needed light.
Typically, a light source employed in a backlight module is one or more cold cathode fluorescence lamps (CCFLs) or one or more light-emitting diodes (LEDs).
LEDs are semiconductors that convert electrical energy into light. Compared to CCFLs, LEDs generate less heat, and have a higher energy conversion efficiency, higher radiance (that is, they emit a larger quantity of light per unit area), longer service lifetime, higher response speed, and better reliability.
It is known that white light is a mixture of different wavelengths across the visible light spectrum. Traditional LEDs cannot produce white light. Instead, each LED can only produce light in one very narrow frequency band. Generally, a combination of light in three primary colors, i.e. a mixture of red, green, and blue light, produces white light. In fact, any color of light may be produced with an appropriate combination of these three colors of light. By combining red, green, and blue LEDs in a tightly packed pattern, an impure form of white light is produced.
Referring to FIG. 7, a typical LED light source of a backlight module is shown. The LED light source 10 includes a plurality of LED modules 11. Each LED module 11 includes a plurality of circuit boards 111, and a plurality of white light units 112 located on the circuit boards 111. Each white light unit 112 includes two green LEDs 1121, a red LED 1122, and a blue LED 1123. From left to right or from top to bottom, one of the green LEDs 1121, the red LED 1122, the blue LED 1123, and the other green LED 1121 of each of the white light units 112 are arranged in a line in that order.
In the LED light source 1 0, heat generated by each of the white light units 112 is small. However, in order to obtain a higher intensity light emission from the LED light source 10, each LED module 11 should include a plurality of white light units 112. Because the green LEDs 1121, the red LED 1122, the blue LED 1123 of the white units 112 are arranged in the lines, too much heat is easily generated in a localized area of the LED light source 10, which can be difficult to dissipate. As a result, overheating in the localized area of the LED light source 10 may occur. In addition, the alternating ordering of the green LEDs 1121, the red LED 1122, and the blue LED 1123may cause difficulties in assembly of the LED modules 11.
Therefore, what is needed is a new LED light source and a backlight module using the LED light source which can overcome the above-described shortcomings.